Association of PEAR1 genetic variants with platelet reactivity in response to dual antiplatelet therapy with aspirin and clopidogrel in the Chinese patient population after percutaneous coronary intervention

Effect of PEAR1, PTGS1 gene polymorphisms on the recurrence of aspirin-treated patients with ischemic stroke in the Han population of China: A 4-year follow-up study

Platelet endothelial aggregation receptor 1 (PEAR1) and prostaglandin endoperoxide synthase 1 (PTGS1) polymorphisms can affect laboratory aspirin resistance. However, the impact of genetic polymorphisms on the recurrence of ischemic stroke (IS) patients treated with aspirin is not fully understood. This study aimed to examine the relationship between gene polymorphisms of PEAR1 and PTGS1 and IS recurrence in patients treated with aspirin. Peripheral blood samples were collected from 174 patients with nonrecurrent IS and 34 with recurrent IS after aspirin treatment. Follow-up was performed on all patients. PEAR1 rs12041331 and PTGS1 rs10306114 polymorphisms were determined using the PCR fluorescence probe method. And the correlations of them with the clinical characteristics were examined by multivariable logistic regression analysis. The distribution frequencies of PEAR1 rs12041331 and PTGS1 rs10306114 genotypes were in Hardy-Weinberg equilibrium, and there was no significant difference in the distribution of PEAR1 rs12041331 polymorphism. Compared to the nonrecurrent group, the AA genotype of the PTGS1 polymorphism was more frequent in the recurrent group (59.77% vs 35.29%, P = .003), and the A allele also showed a higher frequency than the G allele in the recurrent group (P = .001). Multivariable logistic regression analysis showed that smoking (OR = 5.228, 95% CI: 1.938-14.102, P = .001), coronary heart disease (OR = 4.754, 95% CI: 1.498-15.089, P = .008), and the polymorphism at PTGS1(A>G) AA/AG + GG (OR = 2.955, 95% CI: 1.320-6.616, P = .008) were independently associated with IS recurrence in Chinese patients. Our findings suggested that PTGS rs10306114 polymorphisms should receive more attention in the use of aspirin in patients with IS.

Epoxidase inhibitor-aspirin resistance and the relationship with genetic polymorphisms: a review

Strokes are the leading cause of death in most regions of the world. Epoxidase inhibitors include the drug aspirin (acetylsalicylic acid). Aspirin is widely used as first-line treatment for the prevention of cardiovascular and cerebrovascular diseases in at-risk patients. However, patients using conventional doses of aspirin can still develop ischaemic cardiovascular and cerebrovascular diseases, a phenomenon known as aspirin resistance. The occurrence of aspirin resistance hinders the prevention and treatment of ischaemic cardiovascular and cerebrovascular diseases. There are many factors affecting aspirin resistance, such as sex, drug dose, metabolic disease, genetic polymorphisms, drug interactions and pharmacokinetics. Genetic polymorphism refers to the simultaneous and frequent presence of two or more discontinuous variants or genotypes or alleles in a population of organisms. Platelets contain a large number of highly polymorphic transmembrane glycoprotein receptors encoded by two or more isomeric alleles. Changes in gene polymorphisms in various pathways during platelet aggregation can lead to aspirin resistance. This narrative review describes the gene polymorphisms that have been demonstrated to be significantly associated with aspirin resistance. Research on the mechanisms of aspirin resistance and increased knowledge should provide accurate drug guidance in individuals that require first-line antiplatelet therapy.

Therapeutic Effects of Traditional Chinese Medicine for Patients With Coronary Heart Disease After Treatment of Revascularization: A Prospective Cohort Study in the Northern of China

Aim: To investigate the compliance and the outcome of Traditional Chinese Medicine (TCM) in patients with coronary heart disease (CHD) after treatment of revascularization.

Methods: In this prospective cohort study, the non-exposure group (NEG), low-exposure group (LEG), and high-exposure group (HEG) were divided after 2 years follow-up. The primary outcome was a composite of death from cardiovascular causes, non-lethal myocardial infarction, heart transplantation, or stroke. Time-to-event data were evaluated by using the Cox regression analysis with hazard ratios (HRs) and 95% CIs. Then, the two-sided p-values were calculated by using the Cox models. In order to indicate the therapeutic effects of TCM on the CHD after revascularization, the survival analysis and the nested case–control study were conducted separately.

Results: There were 1,003 patients with CHD enrolled, 356 patients (35.49%) did not choose the TCM, 379 patients (37.79%) used the TCM seldom, and only 268 patients (26.72%) used TCM regularly. A total of 653 patients with revascularization participated in the prospective cohort study. Over the duration of the trial, the primary endpoints occurred in 12 (4.35%), 11 (4.80%), and 2 (1.35%) patients in the NEG, LEG, and HEG, while the secondary endpoints occurred in 84 (30.43%), 57 (24.89%), and 15 (10.14%) patients in the NEG, LEG, and HEG, respectively. The occurrence time of secondary endpoint events in HEG was significantly postponed (p < 0.001) compared with the other cohorts. The Cox regression analysis indicated that the HRs in the primary endpoints, the secondary endpoint events, the major adverse cardiac and cerebrovascular events (MACCE), and the composite endpoint events for HEG were all around 0.3 (p < 0.05) and HRs for LEG were all around 0.8. The results of the nested case–control study showed that the TCM exposure was significantly different between the cases and controls in the secondary endpoints (p < 0.05), while no significant difference in the primary endpoints (p > 0.05), but the percentage of HEG in the cases was extremely lower than the controls.

Conclusion: The HEG-TCM may improve the outcomes of the patients with CHD after treatment of revascularization.

Registration:http://www.chictr.org.cn. Unique identifier: ChiCTR-OOC-17012995.

Gene polymorphisms of insulin secretion signaling pathway associated with clopidogrel resistance in Han Chinese population

BACKGROUND

Due to the loss of responsiveness to insulin, diabetes mellitus (DM) patients develop increased platelet reactivity and reduced response to antiplatelet agents. Nevertheless, the relationship between the single-nucleotide polymorphisms (SNP) of the signal pathway gene of insulin secretion and the effect of clopidogrel is elusive.

METHODS

Blood samples were collected from patients administered with dual-antiplatelet therapy (clopidogrel, 75 mg, once daily and aspirin, 100 mg, once daily) after 5 days and completed test within 4 h. The VerifyNow P2Y12 assay was used to measure the platelet functions, and the results were expressed as a P2Y12 reaction unit (PRU). Notably, the selected SNPs were analyzed to demonstrate the functionality of genetic variants.

RESULTS

Analysis of the study population showed that old age, lower plasma albumin (ALB) level, higher creatinine (CREA) level, higher uric acid (UA) level, lower platelet (PLT) count, and lower plateletcrit (PCT) potentially increased the risk of clopidogrel resistance. In a single-nucleotide polymorphism rs6056209 of the PCLB1 gene, the AG genotype was a risk factor for clopidogrel resistance (p < 0.05, OR = 1.574). Similarly, the CC and AG genotype in GNAS rs7121 and CCKAR rs1800857 were protective factors (p < 0.05, OR = 0.094; p <0.05, OR = 0.491). TT was a protective factor in rs10814274 of the CREB3 gene (p < 0.05, OR = 0.444). In the RAPGEF4 gene polymorphism rs17746510, TG was the protective genotype, and the TT genotype was a risk factor for clopidogrel resistance. GCG rs5645 was confirmed; there was a relationship between genotypes containing A or G and clopidogrel resistance.

CONCLUSION

Single-nucleotide polymorphisms of insulin secretion signaling pathway genes trigger clopidogrel resistance.

Platelet Endothelial Aggregation Receptor 1 Polymorphism Is Associated With Functional Outcome in Small-Artery Occlusion Stroke Patients Treated With Aspirin

Background: The role of genetic polymorphisms is important in defining the patient's prognosis and outcomes in coronary artery disease. The present study aimed to explore the association between platelet endothelial aggregation receptor 1 (PEAR1) rs12041331 polymorphism and the outcomes in patients with acute ischemic stroke treated with aspirin or dual antiplatelet therapy (DAPT) with clopidogrel.

Methods: A total of 868 ischemic stroke patients admitted to our hospital from January 1, 2016 to December 30, 2018 were retrospectively studied. The Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification defined stroke subtypes. These patients were treated with aspirin alone or DAPT. The genotype distribution of PEAR1 rs12041331 single-nucleotide polymorphism (AA, AC, and CC) between different TOAST subtypes and treatment groups was assessed, and the clinical impact of genetic variants on functional outcomes defined by the National Institutes of Health Stroke Scale, modified Rankin Scale, and Barthel Index was analyzed using univariate and multivariate logistic regression models.

Results: Among the 868 stroke patients, the PEAR1 AA genotype was 16%, GA was 47%, and GG was 36%. Forty-four percent had aspirin alone, and 56% had DAPT. Overall, the distribution of PEAR single-nucleotide polymorphism was not significant among the two treatment groups or subtypes of TOAST. In contrast, in patients treated with aspirin alone, PEAR1 AA tended to be higher in the small-artery occlusion (SAO) subtype when compared with the no-lacunar subtype, including cardioembolism and large-artery atherosclerosis. PEAR1 AA genotype was significantly associated with favorable functional outcomes at day 7 and discharge only in SAO patients treated with aspirin alone compared with the GG genotype. Multivariate regression models further suggested that AA genotype was independently associated with favorable outcomes in this group after being adjusted for three common stroke risk factors such as age, hypertension history, and C-reactive protein level [odds ratio (OR) 0.23, 95% confidence interval (CI), 0.07–0.64, P = 0.02 for 7-day National Institutes of Health Stroke Scale; OR 0.2, 95% CI, 0.06–0.66, P = 0.03 for 7-day modified Rankin Scale, and OR 0.25, 95% CI, 0.08–0.72, P = 0.03 for 7-day Barthel Index, respectively].

Conclusion: The impact of PEAR1 rs12041331 polymorphism on aspirin depends on the TOAST subtype. PEAR1 AA carrier with SAO stroke is most sensitive to aspirin therapy. PEAR1 AA is an independent factor for the short-term functional outcomes in SAO patients treated with aspirin alone.

Clinical Registration Number: 1800019911.

PEAR1 polymorphisms as a prognostic factor in hemostasis and cardiovascular diseases

Platelet Endothelial Aggregation Receptor (PEAR1), as a platelet receptor, plays a vital role in hemostasis. This receptor, by its extracellular part, causes platelet adhesion and consequently initiates platelet aggregation. Dysfunction of PEAR1 can disrupt platelet aggregation in patients with cardiovascular diseases (CVDs). The content used in this paper has been taken from English language articles (2005-2020) retrieved from Pubmed database and Google scholar search engine using "Cardiovascular Disease", "PEAR1", "Polymorphism", and "Platelet Aggregation" keywords. Some PEAR1 polymorphisms can disrupt homeostasis and interfere with the function mechanism of cardiac drugs. Since polymorphisms in this gene affect platelet function and the platelet aggregation process, PEAR1 could be further studied in the future as an essential factor in controlling the treatment process of patients with cardiovascular diseases. PEAR1 polymorphisms through disruption of the platelet aggregation process can be a risk factor in patients with CVDs. Therefore, controlling patients through genetic testing and the evaluation of PEAR1 polymorphisms can help improve the treatment process of patients. According to the studies on the PEAR1 gene and the effect of different polymorphisms on some crucial issues in CVDs patients (changes in platelet activity), it is clear that if there is a significant relationship between polymorphisms and CVDs, they can be used as prognostic and diagnostic markers. This study aims to evaluate the prognosis and drug treatment of the PEAR1 gene in CVDs patients.

Variation of PEAR1 DNA methylation influences platelet and leukocyte function

BACKGROUND

Platelet-endothelial aggregation receptor 1 (PEAR-1) is a transmembrane receptor involved in platelet activation and megakaryopoiesis whose expression is driven by DNA methylation. PEAR1 variants were associated with differential platelet response to activation and cardiovascular outcomes. We aimed at investigating the link between PEAR1 methylation and platelet and leukocyte function markers in a family-based population.

RESULTS

We measured PEAR1 methylation in 605 Moli-family participants with available blood counts, plasma P-selectin and C-reactive protein, whole blood platelet P-selectin, and platelet-leukocyte mixed conjugate measurements. We performed principal component analysis (PCA) to identify groups of highly correlated CpG sites. We used linear mixed regression models (using age, gender, BMI, smoking, alcohol drinking, being a proband for family recruitment, being a member of myocardial infarction (MI) family as fixed effects, and family as a random effect) to evaluate associations between PEAR1 methylation and phenotypes. PEAR1 methylation Factor2, characterized by the previously identified megakaryocyte-specific CpG sites, was inversely associated with platelet-monocyte conjugates, P-selectin, and WBC counts, while positively associated with the platelet distribution width (PDW) and with leukocyte CD11b and L-selectin. Moreover, PEAR1 Factor2 methylation was negatively associated with INFLAscore, a low-grade inflammation score. The latter was partially mediated by the PEAR1 methylation effect on platelet variables. PEAR1 methylation association with WBC measurements and INFLAscore was confirmed in the independent cohort FLEMENGHO.

CONCLUSIONS

We report a significant link between epigenetic signatures in a platelet functional gene and inflammation-dependent platelet function variability measured in two independent cohorts.

Effect of 106PEAR1 and 168PTGS1 genetic polymorphisms on recurrent ischemic stroke in Chinese patient

The impact of genetic polymorphisms on the occurrence of recurrent ischemic stroke (RIS) is not fully understood. This study was aimed to examine the relationships among the 106PEAR1 and 168PTGS1 polymorphisms and RIS.This was a single-center, retrospective, case-control study of patients seen in consultation between March 2016 and December 2016 at the Shandong Provincial Hospital. The 106PEAR1 (G>A) and 168PTGS1 (-842A>G) polymorphisms were determined by fluorescence in situ hybridization.There were 56 patients with RIS and 137 with initial stroke. Compared with the initial group, the RIS group showed lower LDL-C levels (P = .04). 168PTGS1 (-842A>G) did not meet the Hardy-Weinberg equilibrium. The AA genotype of the 106PEAR1 (G>A) polymorphism was more frequent in the RIS group (17.9% vs 5.8%, P = .009). The A allele also showed a higher frequency than the G allele in the RIS group (P = .02). The multivariable logistic regression analysis showed that 106PEAR1 (G>A) (OR = 3.24, 95%CI: 1.04-10.14, P = .04) and lipid-lowering agents (OR = 9.18, 95%CI: 4.48-18.84, P < .001) were independently associated with RIS.The polymorphism at 106PEAR1 (G>A) was independently associated with RIS in Chinese patients. The assessment of genetic polymorphisms in the prediction of RIS warrants further investigation in order to improve patient management and prognosis after a first ischemic stroke.

Impact of genetic polymorphisms on platelet function and response to anti platelet drugs

Cardiovascular genomic consists in the identification of polymorphic genes responsible for the susceptibility to cardiovascular disease including coronary artery disease (CAD). Genes involved in platelet activation and aggregation play a key role in the predisposition to CAD. A considerable inter-variability of platelet response to agonists and to drugs exists and in particular the hyper-reactivity phenotype seems to be heritable. Besides glycoproteins and receptors expressed on platelets surface whose mutations significantly impact on platelet function, moreover researchers in the last decades have paid great attention to the genes involved in the response to anti-platelet drugs, considering their pivotal role in the treatment and outcomes of CAD patients especially those undergoing PCI. With the outbreak of advanced techniques developed to analyse human genetic footprints, researchers nowadays have shifted from genetic linkage analysis and a candidate gene approach toward genome-wide association (GWAS) studies and the analysis of miRNA-mRNA expression profiles.

Pharmacogenetic and clinical predictors of response to clopidogrel plus aspirin after acute coronary syndrome in Egyptians

OBJECTIVES

Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel reduces the risk for recurrent cardiovascular events after acute coronary syndrome (ACS). However, there is significant variation in response to DAPT that may be influenced by both genetic and nongenetic factors. This study aimed to assess the effect of genetic polymorphisms in PON-1, PEAR-1, P2Y12, CES1, and CYP2C19, along with clinical, demographic, and social factors, on variation in response to DAPT in Egyptians.

PARTICIPANTS AND METHODS

This study included 230 Egyptians treated with clopidogrel 75 mg/day and aspirin 81 mg/day for at least 12 months following their first ACS. Simple and multivariable logistic regression analyses were carried out to identify factors associated with major adverse cardiovascular events (MACE), defined as the occurrence of recurrent ACS, ischemic stroke, stent-related revascularization, or death, in clopidogrel-treated participants.

RESULTS

Using multivariable logistic regression analysis, the CYP2C19*2 polymorphism was the only genetic predictor of MACE [odds ratio (OR): 2.23, 95% confidence interval (CI): 1.15-4.33, P=0.01]. In addition, proton pump inhibitor use (OR: 4.77, 95% CI: 1.47-15.54, P=0.009) and diabetes (OR: 1.83, 95% CI: 1.03-3.26, P=0.03) were associated with higher cardiovascular risk, whereas statin use was associated with lower risk (OR: 0.43, 95% CI: 0.25-0.76, P=0.003). The contribution of these four genetic and nongenetic factors explained 19% of the variability in risk for MACE in Egyptians treated with DAPT.

CONCLUSION

These results highlight that CYP2C19*2, along with diabetes, and use of proton pump inhibitor and statin are important factors jointly associated with variability in clinical response to DAPT following ACS in Egyptians.

Variants of PEAR1 Are Associated With Outcome in Patients With ACS and Stable CAD Undergoing PCI

Introduction: Platelet endothelial aggregation receptor 1 (PEAR1) triggers platelet aggregation and is expressed in platelets and endothelial cells. Genome-wide association studies (GWAS) showed an association between platelet function and single-nucleotide polymorphisms (SNPs) in PEAR1.

Methods: In 582 consecutive patients with stable coronary artery disease (CAD) or acute coronary syndrome (ACS) scheduled for PCI and treated with ASA and Clopidogrel, Prasugrel, or Ticagrelor, SNP analysis for rs12566888, rs2768759, rs41273215, rs3737224, and rs822442 was performed. During a follow-up period of 365 days after initial PCI, all patients were tracked for a primary endpoint, defined as a combined endpoint consisting of either time to death, myocardial infarction (MI) or ischemic stroke. All cause mortality, MI and ischemic stroke were defined as secondary endpoints.

Results: Multivariable Cox model analysis for the primary endpoint revealed a significantly increased risk in homozygous PEAR1 rs2768759 minor allele carriers (hazard ratio, 3.16; 95% confidence interval, 1.4–7.13, p = 0.006). Moreover, PEAR1 rs12566888 minor allele carriers also showed an increased risk in all patients (hazard ratio, 1.69; 95% confidence interval, 0.87–3.27, p = 0.122), which was marginally significant in male patients (hazard ratio, 2.12; 95% confidence interval, 1.02–4.43, p = 0.045; n = 425).

Conclusions: To the best of our knowledge, this is the first study showing that distinct genetic variants of PEAR1 are associated with cardiovascular prognosis in high risk patients undergoing PCI and treated with dual anti platelet therapy.

Effect of PEAR1 Genetic Variants on 1-Year Outcomes in Chinese Patients with Acute Myocardial Infarction After Percutaneous Coronary Intervention

AIMS

Platelet endothelial aggregation receptor-1 (PEAR1) is a platelet transmembrane protein that plays an important role on platelet aggregation. The aim of this study was to investigate whether PEAR1 genetic variations are associated with 1-year outcomes in Chinese patients with acute myocardial infarction after percutaneous coronary intervention.

METHODS

A total of 647 consecutive Chinese patients with acute myocardial infarction that underwent percutaneous coronary intervention and that were exposed to standard dual antiplatelet therapy with aspirin and clopidogrel were enrolled in this study. Six single nucleotide polymorphisms of PEAR1 were detected using the ligase detection reaction method. The follow-up period was 12 months.

RESULTS

Overall, 66 (10.2%) adverse ischemic events occurred. Multivariate Cox regression analysis showed that carriage of the PEAR1 rs56260937 minor allele was an independent predictor of revascularization events (OR=2.15, 95% CI 1.12-4.15, p=0.022) after adjusting for confounding factors.

CONCLUSIONS

Genetic testing for PEAR1 variants can be helpful in predicting adverse ischemic events in Chinese patients with acute myocardial infarction after percutaneous coronary intervention.

Study of the Association of PEAR1, P2Y12, and UGT2A1 Polymorphisms with Platelet Reactivity in Response to Dual Antiplatelet Therapy in Chinese Patients

Objectives: Genetic variation is thought to contribute to considerable interindividual variability in platelet function, and there is a pressing need to identify genetic markers that can be used to predict the response to treatment. Our study investigated whether PEAR1, P2Y12, and UGT2A1 polymorphisms were associated with platelet reactivity in response to dual antiplatelet therapy in Chinese patients with acute coronary syndrome. Methods: Patients with inhibition of platelet aggregation (IPA) < 30% after treatment were classified as the high platelet reactivity (HPR) group. Patients with IPA > 30% were classified as the normal platelet reactivity (NPR) group. ADP-induced platelet aggregation was measured by thromboelastography (TEG) platelet-mapping assay. Thirteen single nucleotide polymorphisms (SNPs) of PEAR1, P2Y12 and UGT2A1 were genotyped using the Mass­ARRAY platform. Results: Seven SNPs were significantly associated with ADP-induced platelet aggregation by univariate analysis. Major allele G at rs12041331, minor allele G at rs2644592, minor allele C at rs11264580, and minor allele C at rs11249454 were significantly associated with HPR, whereas minor allele T at rs57731889, minor allele A at rs16863356, and minor allele T at rs7634096 were significantly associated with NPR. The mean IPA was significantly lower in patients suffering recurrent ischemic events than in patients without recurrent events in our study (p = 0.048). Conclusions: Our findings suggest that PEAR1, P2Y12, and UGT2A1 genetic variants may be potential biomarkers that can be used to guide clinical applications of clopidogrel and aspirin in Chinese patients.

Genetic mutations in PEAR1 associated with cardiovascular outcomes in Chinese patients with acute coronary syndrome

OBJECTIVE

To investigate the association between PEAR1 (platelet endothelial aggregation receptor-1) polymorphisms and cardiovascular outcomes in acute coronary syndrome (ACS) in patients treated with aspirin and clopidogrel.

METHODS

We genotyped eight common PEAR1 SNPs (rs2768759, rs12566888, rs12041331, rs11264579, rs2644592, rs822441, rs822442, and rs4661012), also CYP2C19*2 (rs4244285) and CYP2C19*3 (rs4986893) in 196 Chinese patients with ACS. We assessed the association between PEAR1 polymorphisms and platelet inhibition rate (PIR) measured by thromboelastography (TEG). The ischemic events over 12 months were recorded, and the relationship between PEAR1 polymorphisms and ischemic events was analyzed.

RESULTS

Genetic mutations in rs822441, rs822442, and CYP2C19^⁎2/^⁎3 alleles were significantly associated with a decrease in PIR induced by adenosine diphosphate (ADP). Carriers of the T allele in rs11264579 were less likely to have ischemic events compared with non-carriers (HR: 0.53, 95% CI: 0.30-0.94, P = .031). By contrast, carriers of the A allele in rs822442 had increased risk of ischemic events (HR: 1.82, 95% CI: 1.02-3.24, P = .043). However, these significant associations disappeared after controlling family-wise error rate.

CONCLUSIONS

For Chinese patients with ACS treated with aspirin and clopidogrel, genetic mutations in rs822441/rs822442 in PEAR1 correlated significantly with platelet activity after adjusting for CYP2C19 *2/*3 alleles. The rs11264579 T allele might be a protective factor for ischemic events; rs11264579, rs822441, and rs822442 might be genetic markers worthy of further research.

Pharmacokinetic and Pharmacodynamic Responses to Clopidogrel: Evidences and Perspectives

Clopidogrel has significantly reduced the incidence of recurrent atherothrombotic events in patients with acute coronary syndrome (ACS) and in those undergoing percutaneous coronary intervention (PCI). However, recurrence events still remain, which may be partly due to inadequate platelet inhibition by standard clopidogrel therapy. Genetic polymorphisms involved in clopidogrel’s absorption, metabolism, and the P2Y12 receptor may interfere with its antiplatelet activity. Recent evidence indicated that epigenetic modification may also affect clopidogrel response. In addition, non-genetic factors such as demographics, disease complications, and drug-drug interactions can impair the antiplatelet effect of clopidogrel. The identification of factors contributing to the variation in clopidogrel response is needed to improve platelet inhibition and to reduce risk for cardiovascular events. This review encompasses the most recent updates on factors influencing pharmacokinetic and pharmacodynamic responses to clopidogrel.

Association of PEAR1 rs12041331 polymorphism and pharmacodynamics of ticagrelor in healthy Chinese volunteers

1. Genetic polymorphisms in platelet endothelial aggregation receptor 1 (PEAR1) were associated with responsiveness to aspirin and P2Y12 receptor antagonists. This study aimed to investigate whether PEAR1 polymorphism is associated with ticagrelor pharmacodynamics in healthy Chinese subjects. 2. The in vitro inhibition of platelet aggregation (IPA) was evaluated before and after ticagrelor incubated with platelet-rich plasma from 196 healthy Chinese male subjects. Eight polymorphisms at PEAR1 locus were genotyped. Eighteen volunteers (six in each rs12041331 genotype group) were randomly selected. After a single oral 180 mg dose of ticagrelor, plasma levels of ticagrelor and the active metabolite AR-C124910XX were measured and pharmacodynamics parameters including IPA and VASP-platelet reactivity index (PRI) were assessed. 3. No significant difference in ticagrelor pharmacokinetics among rs12041331 genotype was observed. As compared with rs12041331 G allele carriers, AA homozygotes exhibited increased IPA after 15 μM ticagrelor incubation (p < 0.01), increased area under the time-effect curve of IPA and lower PRI at 2 h after ticagrelor administration (p < 0.05, respectively). Rs4661012 GG homozygotes showed increased IPA after 50 μM ticagrelor incubation as compared to T allele carriers (p < 0.01). 4. PEAR1 polymorphism may influence ticagrelor pharmacodynamics in healthy Chinese subjects.

Prospective Evaluation of Genetic Variation in Platelet Endothelial Aggregation Receptor 1 Reveals Aspirin-Dependent Effects on Platelet Aggregation Pathways

Genetic variation in the platelet endothelial aggregation receptor 1 (PEAR1) gene, most notably rs12041331, is implicated in altered on‐aspirin platelet aggregation and increased cardiovascular event risk. We prospectively tested the effects of aspirin administration at commonly prescribed doses (81, 162, and 324 mg/day) on agonist‐induced platelet aggregation by rs12041331 genotype in 67 healthy individuals. Prior to aspirin administration, rs12041331 minor allele carriers had significantly reduced adenosine diphosphate (ADP)‐induced platelet aggregation compared with noncarriers (P = 0.03) but was not associated with other platelet pathways. In contrast, rs12041331 was significantly associated with on‐aspirin platelet aggregation when collagen and epinephrine were used to stimulate platelet aggregation (P < 0.05 for all associations), but not ADP. The influence of PEAR1 rs12041331 on platelet aggregation is pathway‐specific and is altered by aspirin at therapeutic doses, but not in a dose‐dependent manner. Additional studies are needed to determine the impact of PEAR1 on cardiovascular events in aspirin‐treated patients.

PEAR1 gene polymorphism in a Chinese pedigree with pulmonary thromboembolism

To explore the correlation between platelet endothelial aggregation receptor-1 (PEAR1) genetic polymorphism and pulmonary thromboembolism (PTE).Variant loci of the PEAR1 gene were screened in a PTE pedigree, followed by verification using Sanger sequencing. These polymorphic loci were validated in 101 PTE patients and 132 matched normal patients using MassARRAY single nucleotide polymorphism (SNP) genotyping methods. The frequency differences between the allele and genotypes were compared using the Hardy-Weinberg equilibrium test and Chi-square test. The correlation between the PEAR1 gene SNP and PTE was analyzed by comparing the between-group variance differences using the χ test.Three SNPs were identified in the PTE pedigree. There was a heterozygous transition of T>C in rs1952294, and a transition of C>T in rs778026543 in 2 members in the pedigree; however, the rs778026543 was not identified in the 101 PTE patients and 132 healthy controls. The genotype and allele frequencies of rs822442 did not differ significantly between PTE patients and healthy controls (P > 0.05). The variance difference at rs778026543 between pedigree members and healthy controls was significant (P < 0.001), supporting its potential heredity.The PEAR1 polymorphism, rs778026543, but not rs1952294 and rs822442, may be a susceptibility SNP for PTE.

Allele-specific DNA methylation reinforces PEAR1 enhancer activity

Genetic variation in the PEAR1 locus is linked to platelet reactivity and cardiovascular disease. The major G allele of rs12041331, an intronic cytosine guanine dinucleotide-single-nucleotide polymorphism (CpG-SNP), is associated with higher PEAR1 expression in platelets and endothelial cells than the minor A allele. The molecular mechanism underlying this difference remains elusive. We have characterized the histone modification profiles of the intronic region surrounding rs12041331 and identified H3K4Me1 enhancer-specific enrichment for the region that covers the CpG-SNP. Interestingly, methylation studies revealed that the CpG site is fully methylated in leukocytes of GG carriers. Nuclear protein extracts from megakaryocytes, endothelial cells, vs control HEK-293 cells show a 3-fold higher affinity for the methylated G allele compared with nonmethylated G or A alleles in a gel electrophoretic mobility shift assay. To understand the positive relationship between methylation and gene expression, we studied DNA methylation at 4 different loci of PEAR1 during in vitro megakaryopoiesis. During differentiation, the CpG-SNP remained fully methylated, while we observed rapid methylation increases at the CpG-island overlapping the first 5'-untranslated region exon, paralleling the increased PEAR1 expression. In the same region, A-allele carriers of rs12041331 showed significantly lower DNA methylation at CGI1 compared with GG homozygote. This CpG-island contains binding sites for the methylation-sensitive transcription factor CTCF, whose binding is known to play a role in enhancer activation and/or repression. In conclusion, we report the molecular characterization of the first platelet function-related CpG-SNP, a genetic predisposition that reinforces PEAR1 enhancer activity through allele-specific DNA methylation.